Grabbing a random line from file

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You would probably want to look at the node.js standard library function for reading files, fs.readFile, and end up with something along the lines of:

const fs = require("fs");
// note this will be async
function getRandomLine(filename, callback){
  fs.readFile(filename, "utf-8", function(err, data){
    if(err) {
        throw err;
    }

    // note: this assumes `data` is a string - you may need
    //       to coerce it - see the comments for an approach
    var lines = data.split('\n');
    
    // choose one of the lines...
    var line = lines[Math.floor(Math.random()*lines.length)]

    // invoke the callback with our line
    callback(line);
 })
}

If reading the whole thing and splitting isn’t an option, then maybe have a look at this stack overflow for ideas.

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